26 - 04 - 2015

VNC socket with Libivrt incorrect permissions

We you are using libvirt with VNC based on sockets instead of default TCP listening and you are not running as root. You could have an situation when socket has incorrect permissions 0775 and qemu:qemu group under default /var/lib/libvirt/qemu folder. The files has extension ".vnc" with suffix based on your Virtual Machine name and "=" sign.

Unix sockets are forced by "vnc_auto_unix_socket" in qemu.conf file, in /etc/libvirt folder.

The params from libvirtd.conf unix_sock_rw_perms and unix_sock_ro_perms, had no impact on the VNC socket permissions.

To change the VNC group permissions set:

/etc/libvirt/qemu.conf

# The group for QEMU processes run by the system instance. It can be
# specified in a similar way to user.
group = "users"
This will allow users from group "users" to open the socket.

 

L3VPN on Cisco XR - without MPLS enabled switches

You can be put in situation to connect two or more L3 devices using L3VPN. The configuration isn't complex, and will work unless the path between devices invloves the non-MPLS enabled switches. If you connect ASR routers using other devices in the network it can be tricky. BGP sessions is not an issue, but MPLS tags. For L3VPN two labels are required:

  • Outer Label - specifices outgoing interface to reach L3VPN enabled neighbor.
  • Inner Label - provides information about VRF instance for the neighbor

The issue I got was lack of Outer Label because the path toward L3VPN neighor was not MPLS-enabled. It was simply 802.1Q subinterface, on top of bundle-interface. The sessions have been established, but no traffic was seen on opposite site.

Read more: L3VPN on Cisco XR - without MPLS enabled switches

Configuring netbsd (sparc) appliance for IOU

There are alot of articles covering subject of IOU running on Linux and Unix. I would like to go deeper and specific how we can create some useful confiugration on NETBSD/SPARC to have this maybe easier in some cases.

The goals I've set are:

  • Ony one IOU instance per NETBSD appliance
  • Use GNS3 clouds (UDP TAP) to provide connectivity between each NETBSD instance and other part of networks. This was really forced, in first instance I tried to create some kind of bridge, but NETBSD didn't recognize second LE (ethernet card) correctly
  • Make it as more automaticated as it is possible
  • Keeps each service separated

Read more: Configuring netbsd (sparc) appliance for IOU

openvswitch - libvirtd issue fix - veth already existing

Some time ago I wrote an little fix for running openvswitch network solution combined with libvirtd. It seems that a few days ago after upgrading my openSUSE 13.1 packages, openvswitch saves conf.db little bit different as it was. 

Read more: openvswitch - libvirtd issue fix - veth already existing

Missing nvidia DKMS module after system update

I had few times situation when after system update had incorrect sequence. What I mean, it updated nvidia dkms module first and a few packages later kernel was updated. This lead to missing nividia DKMS module during boot, and in my case booting without X11...

The fix of this issue is very trivial, but might be useful for beginners.

Read more: Missing nvidia DKMS module after system update

Running ESXi 5.1 on QEMU/KVM

You may want to run ESXi nested in QEMU/KVM but without re-compiling qemu source it's not possible. The try without the fix fails with pinky screen:

Read more: Running ESXi 5.1 on QEMU/KVM

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